very simply version

game_backuper/backuper.py

@@ -0,0 +1,58 @@
+from game_backuper.db import Db
+from game_backuper.config import Config, Program
+from game_backuper.cml import Opts
+from threading import Thread
+from os.path import exists, join
+from os import mkdir
+from game_backuper.file import new_file, copy_file
+
+
+class BackupTask(Thread):
+    def __init__(self, prog: Program, db: Db, cfg: Config):
+        Thread.__init__(self, name=f"Backup_{prog.name}")
+        self.cfg = cfg
+        self.prog = prog
+        self.db = db
+
+    def run(self):
+        self.prog.clear_cache()
+        prog = self.prog.name
+        bp = join(self.cfg.dest, prog)
+        if not exists(bp):
+            mkdir(bp)
+        for f in self.prog.files:
+            if exists(f[1]):
+                ori = self.db.get_file(prog, f[0])
+                nf = new_file(f[1], f[0], prog)
+                if nf is None:
+                    continue
+                de = join(bp, f[0])
+                if ori is not None:
+                    if ori.size == nf.size and ori.hash == nf.hash:
+                        print(f'{prog}: Skip {f[0]}({f[1]}).')
+                        continue
+                    copy_file(f[1], de, f[0], prog)
+                    self.db.set_file(ori.id, nf.size, nf.hash)
+                else:
+                    copy_file(f[1], de, f[0], prog)
+                    self.db.add_file(nf)
+
+
+class Backuper:
+    def __init__(self, db: Db, config: Config, opts: Opts):
+        self.db = db
+        self.conf = config
+        self.opts = opts
+        self.tasks = []
+
+    def run(self):
+        for prog in self.conf.progs:
+            t = BackupTask(prog, self.db, self.conf)
+            self.tasks.append(t)
+            t.start()
+        self.wait()
+        return 0
+
+    def wait(self):
+        for task in self.tasks:
+            task.join()